Manufacture of carbons for electric lamps



(N0 Mbdel.)

' W. F. SMITH.

MANUFACTURE OF GARBONS FOR ELEGTRIU LAMPS- No. 4 Z Z,895. Patented Mar. 4, 1890.

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UNITED STATES PATENT OFFICE.

\VALTER E. SMITH, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO THE NElV JERSEY.

MANUFACTURE OF CARBONS FOR ELECTRIC LAMPS.

SPECIFICATION forming part of Letters Patent No. 422,895, dated March 4, 1890.

Application filed January 30. 1890. Serial No. 338,615. (No model.)

To all whom it may concern.-

Be it known that I, WALTER F. SMITH, a citizen of the United States, residing at the city of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in the Process of Making Filaments or Pencils for Electric Lamps or Lights, of which the following is a specification.

My invention relates to a process for the manufacture of compound filaments or pencils and applicable to both are lights as well as incandescent lamps.

The principal objects of my invention are, first, to provide an efficient and comparatively economical method for the manufacture of strong and durable filaments or penoils and of a type capable of becoming intensely incandescent and luminous when included in circuit, and, second, to provide a method by which a filamentary body or pencil may be produced having the inner section thereof displaced by a core composed of a material or substances capable of withstanding a high degree of incandescence, yet at the same time a non-conductor of electricity, and of a type capableof serving the twofold purpose of protecting the filament or pencil proper from disintegration or rupture due to sudden rise in temperature through imperfect regulation or other attending causes in the generator, and of increasing the radiatingsurface of the filament or pencil without materially increasing the electrical resistance thereof, and, moreover, with the life prolonged and their utility increased in a greater degree than has heretofore been possible. I

My invention consists in coating or satin rating a core of fibrous or similar material with a compound of zirconium and then dry ing the same, when a carbonizable material is braided, wound, or molded thereon, and the treated article then carbonized, whereby the zirconium is converted into zirconia or other oxide thereof, and the filament or pencil thereby rendered suitable for use in an elec trio lamp or light,

The nature of my present invent-ion wlllbe more fully understood from the following de scription, taken in connection with the ac companying drawings, forming part hereof, and in which Figure 1 is an elevation, 011 an enlarged scale, of a portion of a compound filament or pencil embodying the particular features of my invention and illustrating the braided or wound covering thereof partially removed to expose to view the core; and Fig. 2 is a similar view, on an enlarged scale, of a filament or pencil embodying a modified form of my invention, and also with a portion of the cast or molded covering removed to expose to view the core thereof.

In the drawings, A is a portion of the filament or pencil. B is the core thereof, and C is the envelope or covering surrounding said core.

The manner of carrying out my improved method for the manufacture of the filaments or pencils of the character hereinbefore mentioned is as follows: A wick or strands of fibrous similar material suitably twisted together are saturated with a solution composed of nitrate or other compound of zirconium. The core or supportB is then dried in any preferred manner, when a suitable carbon cover or a conbonizable material C is braided or wound round the same, for instance, in the manner illustrated in Fig. 1, or a carbon cover or other carbonizable material cast or molded around the core B in the manner illustrated, for instance, in Fig. 2. The entire structure, treated in the above manner, is then subjected to a carbonizing process, whereby the nitrate or other compound of zirconium is converted into zirconia or other oxide of zirconium, and the filament or pencil thereby rendered suitable for use in an electric lamp or light.

The particular features of the invention are, first, that a filament or pencilis produced capable in use of becoming intensely incandescent and luminous when included in circuit, and, second, that a filament or pencil is produced with a core capable of not only withstanding a high degree of incandescence, while at the same time being a noncon doctor of electricity, but of serving the two fold purpose of protecting the filament or I00 ing-surface of the filament or pencil Without materially increasing the electrical resistance thereof.

and desire to secure by Letters Patent, is-

1. The method of making a filament or pencil for an electric lamp or light, which consists in saturating a core composed of fibrous material With a compound of zirconium, then drying the structure, then mounting on or surrounding said structure with a carbonizable material, and then carbonizing the same,

substantially as and for the purposes set forth. I

2. The method of making a filament or pencil for an electric lamp or light, which con sists in saturating a core composed of fibrous or similar material with a compound of zirconium, then drying and braiding or winding Having thus described the nature and ob- ;;ects of my invention, What I claim as new, 1

a carbonizable material thereon, and then carbonizing the structure, substantially as and for the purposes set forth.

In Witness whereof I have hereunto set my signature in the presence of two subscribing Witnesses.

WALTER F. SMITH. lVitnesses:

GEO. W. REED, RICHARD O. MAXWELL. 

